Field of the Invention
The present invention relates to a multilayer ceramic capacitor and a board for mounting the same.
Description of the Related Art
A multilayer ceramic capacitor, a multilayer chip electronic component, is a chip-shaped condenser mounted on a printed circuit board of various electronic products such as display devices, for example, liquid crystal displays (LCDs), plasma display panels (PDPs) and the like, computers, smartphones, mobile phones, and the like, to serve to charge and discharge electricity.
Since such a multilayer ceramic capacitor (MLCC) has advantages such as a small size, high capacitance, ease of mounting, or the like, it may be used as a component in various electronic devices.
The multilayer ceramic capacitor may have a structure in which a plurality of dielectric layers and internal electrodes having different polarities are alternately stacked while having the dielectric layer interposed therebetween.
Particularly, in a power supply device for the central processing unit (CPU) of a computer, or the like, voltage noise may be generated during a process of supplying a low amount of voltage, due to rapid changes in load current.
Therefore, such a multilayer ceramic capacitor has been widely used in power supply devices as a decoupling capacitor for suppressing such voltage noise.
The multilayer ceramic capacitor for decoupling should have low equivalent series inductance (ESL) as an operational frequency thereof is increased. Research has been undertaken in order to decrease such ESL.
Further, in order to more stably supply power, the multilayer ceramic capacitor for decoupling should have controllable equivalent series resistance (ESR) characteristics.
In the case in which an ESR value of the multilayer ceramic capacitor is lower than a required level, an impedance peak at a parallel resonance frequency, generated due to the ESL of the capacitor and a plane capacitance of a micro processor package, may increase, and impedance at a series resonance frequency of the capacitor may excessively decrease.
Therefore, in order to allow a user to implement flat impedance characteristics in a power distribution network, the ESR characteristics of the multilayer ceramic capacitor for decoupling should be easily controllable.
With regard to control of the ESR characteristics, the use of a material having a high degree of electrical resistance in external and internal electrodes may be considered. The measure of changing the material as described above may provide high ESR characteristics while maintaining a low ESL structure according to the related art.
However, in the case of using such a material having a high degree of resistance in the external electrodes, a localized heat spot causing a current crowding effect may be generated due to pin holes. Further, in the case of using such a material having a high degree of resistance in the internal electrodes, in order to match the material with a ceramic material in order to implement a high degree of capacitance, the material used for formation of the internal electrodes should also be continuously changed.
Therefore, since the existing measure for controlling ESR has the above-described disadvantages, research into a multilayer ceramic capacitor in which ESR is able to be controlled is still required.
In addition, in accordance with the recent trend for the rapid development of mobile terminals such as tablet personal computers (PCs), ultrabooks, and the like, a micro processor has been converted into a miniaturized and highly integrated product.
Therefore, an area of the printed circuit board has decreased, and a mounting space of the decoupling capacitor has also been limited, and accordingly, a multilayer ceramic capacitor able to be mounted, when limited mounting space is available, is still required.